JP6420166B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner.

  First, the basic configuration of the air conditioner will be described.

  FIG. 4 is a configuration diagram of a general refrigeration cycle used in an air conditioner having operation modes of cooling operation, heating operation, and dehumidifying operation.

  The air conditioner functions when the outdoor unit 1 and the indoor unit 5 are connected by connection pipes 7 and 8. The indoor unit 5 includes a first indoor heat exchanger 21, a second indoor heat exchanger 22, a first expansion device 31, and a blower fan 6. It is provided on the refrigerant flow path connecting the one indoor heat exchanger 21 and the second indoor heat exchanger 22.

  The outdoor unit 1 includes a compressor 2, a four-way valve 3, an outdoor heat exchanger 10, a second expansion device 32, and a blower fan 4. In general, a propeller fan is used for the blower fan 4 and a cross-flow fan is used for the blower fan 6.

  FIG. 5 shows the structure of an element of a general cross fin tube type heat exchanger of the same type as that used in a heat exchanger of an air conditioner. As shown in FIG. 5, the heat exchanger of this type has a structure in which a large number of aluminum fins 101 are penetrated by U-shaped copper heat transfer tubes 102. The fins 101 and the heat transfer tubes 102 are in close contact with each other by expanding the heat transfer tubes 102 inserted into the fins 101 by hydraulic pressure or mechanical expansion. Further, a joint component 103 is welded to the end of the heat transfer tube 102 to form a refrigerant flow path.

  In general, in an air conditioner heat exchanger, a plurality of heat exchangers having the configuration shown in FIG. 5 are arranged in the air flow direction in order to improve efficiency, and the refrigerant flow path in the heat exchanger is provided in the pipe. The number of passes according to the flow rate of refrigerant flowing through

  Next, the operation of each element in each operation mode of the cooling operation, the heating operation, and the dehumidifying operation will be described with reference to FIG.

  First, in the case of the cooling operation, the high-pressure gaseous refrigerant compressed by the compressor 2 is condensed by releasing heat to the outside air in the outdoor heat exchanger 10 and becomes a high-pressure liquid refrigerant. The liquid refrigerant is depressurized by the action of the second throttling device 32, enters a low-temperature low-pressure gas-liquid two-phase state, and flows to the indoor unit 5 through the connection pipe 8.

  The refrigerant that has entered the indoor unit 5 evaporates by absorbing the heat of the indoor air in the first indoor heat exchanger 21 and the second indoor heat exchanger 22. The refrigerant evaporated in the indoor unit 5 returns to the outdoor unit 1 through the connection pipe 7 and is compressed again by the compressor 2 through the four-way valve 3. At this time, the first aperture device 31 is fully open.

  In the heating operation mode, the refrigerant flow path is switched by the four-way valve 3, and the high-pressure gaseous refrigerant compressed by the compressor 2 flows to the indoor unit 5 through the four-way valve 3 and the connection pipe 7. The refrigerant that has entered the indoor unit 5 is condensed by dissipating heat to the indoor air in the second indoor heat exchanger 22 and the first indoor heat exchanger 21, and becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows to the outdoor unit 1 through the connection pipe 8.

  The high-pressure liquid refrigerant that has entered the outdoor unit 1 is depressurized by the action of the second throttling device 32, becomes a low-temperature low-pressure gas-liquid two-phase state, flows to the outdoor heat exchanger 10, and absorbs heat of outdoor air. It evaporates and becomes a gaseous refrigerant. The refrigerant that has become gaseous in the outdoor heat exchanger 10 passes through the four-way valve 3 and is compressed again by the compressor 2. Also in the heating operation mode, the first expansion device 31 is in a fully open state, similarly to the cooling operation mode.

  Next, the operation of each element in the dehumidifying operation mode will be described. In this dehumidifying operation mode, the flow direction of the refrigerant is the same as in the cooling operation mode. That is, the high-pressure gaseous refrigerant compressed by the compressor 2 flows to the indoor unit 5 through the outdoor heat exchanger 10, the second expansion device 32, and the connection pipe 8. The refrigerant that has entered the indoor unit 5 passes through the first indoor heat exchanger 21, the first expansion device 31, and the second indoor heat exchanger 22, returns to the outdoor unit 1 through the connection pipe 7, and the four-way valve 3. Flows again through the compressor 2.

  In the dehumidifying operation mode, the air passing through the second indoor heat exchanger 22 is cooled and dehumidified, and the air passing through the first indoor heat exchanger 21 is heated, thereby reducing the humidity while suppressing the change in the indoor air temperature. Controlled to lower.

  In order to heat the air passing through the first indoor heat exchanger 21, the high-pressure gaseous refrigerant compressed by the compressor 2 is not condensed into the liquid refrigerant by the outdoor heat exchanger 10, and the high-temperature and high-pressure air is not condensed. It is necessary to flow into the indoor unit 5 through the connection pipe 8 while maintaining the liquid two-phase state. For this reason, the second expansion device 32 is controlled to be in the open side or fully open state as compared with the cooling operation mode. The amount of heating in the first indoor heat exchanger 21 is the amount of heat radiated to the outside air by the outdoor heat exchanger 10 by controlling the rotational speed of the blower fan 4 in addition to the opening degree control of the second expansion device 32. To control.

  Although the blower fan 4 is not shown in the figure, it is used for cooling the electrical equipment that controls the compressor 1 and the blower fan 4, so it completely stops even if it operates at low speed or intermittently. Never do.

  With the above control, the refrigerant that has entered the indoor unit 5 while passing through the high-temperature and high-pressure gas-liquid two-phase state passes through the first indoor heat exchanger 21 in the first indoor heat exchanger 21 by the operation of the blower fan 6. It is condensed by dissipating heat to the indoor air, and becomes a liquid refrigerant. Thereby, the air which passes the 1st indoor heat exchanger 21 is heated, and temperature rises.

  Next, the liquid refrigerant flows to the first throttling device 31. In this dehumidifying operation mode, the first throttle device 31 is controlled to be closed so as to have a flow path resistance, and is depressurized by the action of the first throttle device 31 to be in a low-temperature low-pressure gas-liquid two-phase state. It flows to the second indoor heat exchanger 22. The low-temperature low-pressure gas-liquid two-phase refrigerant evaporates in the second indoor heat exchanger 22 by absorbing heat from the air passing through the second indoor heat exchanger 22 by the operation of the blower fan 6. At this time, the air passing through the second indoor heat exchanger 22 is cooled and dehumidified. In this manner, the air is heated in the first indoor heat exchanger 21 and the air is cooled and dehumidified in the second indoor heat exchanger 22, so that the present operation mode is dehumidified while suppressing the temperature change of the indoor air. Making it possible.

  As described above, in the cooling operation mode, the high-temperature and high-pressure refrigerant is liquefied in the outdoor heat exchanger 10, but in the dehumidification operation mode, a high-temperature and high-pressure gas-liquid two-phase state is obtained, and in the dehumidification operation mode, surplus as compared with the cooling operation mode. There will be a new refrigerant. Generally, in the refrigeration cycle, when the refrigerant amount is excessive, the pressure on the cycle high pressure side mainly increases, leading to an increase in the required power of the compressor. Therefore, storing excess refrigerant is effective for improving energy saving in the dehumidifying operation mode.

  In addition, by storing surplus refrigerant in the receiver or outdoor heat exchanger, it is possible to prevent troubles caused by surplus refrigerant in any of the cooling, heating, and dehumidifying operation modes, and to maintain the indoor humidity properly. As a conventional example of a harmony machine, there is one disclosed in Patent Document 1, for example.

  In the conventional example of Patent Document 1, a bypass circuit that guides a part of the refrigerant discharged from the compressor is provided in parallel to the outdoor heat exchanger and the expansion valve, and a flow rate adjusting valve is provided on the path of the bypass circuit. ing. In this configuration, the amount of heating in the indoor unit is secured by controlling the flow rate of the high-temperature and high-pressure gaseous refrigerant discharged from the compressor through the bypass circuit and the flow rate of the refrigerant radiated to the outside air in the outdoor heat exchanger. In addition, it is possible to store excess refrigerant by controlling the opening degree of the expansion device provided at the outlet of the outdoor heat exchanger.

JP 2002-357353 A

  However, the conventional example of Patent Document 1 stores excess refrigerant while ensuring the heating amount of room air by directly flowing a part of high-temperature gaseous refrigerant discharged from the compressor during dehumidification operation into the room. The bypass circuit which guides a part of refrigerant discharged from the compressor is provided in parallel with the outdoor heat exchanger and the expansion valve.

  In the case of this configuration, during cooling operation, the portion through which the high-temperature and high-pressure refrigerant gas flows and the expansion valve outlet portion through which the low-temperature and low-pressure two-phase refrigerant decompressed by the action of the expansion valve flows thermally via a bypass circuit. Will be in touch.

  For this reason, heat is transferred via the bypass circuit from the temperature difference between the low-temperature and low-pressure refrigerant flowing to the indoor unit during cooling operation and the high-temperature and high-pressure gaseous refrigerant near the compressor discharge, and the low-temperature and low-pressure refrigerant There is a possibility that part of the refrigerant in the phase state evaporates, the amount of heat absorbed from the indoor air is reduced by the indoor heat exchanger, and the efficiency is lowered.

  From the above, an object of the present invention is to provide an air conditioner capable of preventing a decrease in efficiency.

  In order to solve the above problems, an air conditioner according to claim 1 of the present invention is an air conditioner in which at least a compressor, an outdoor heat exchanger, and an indoor heat exchanger are connected by a refrigerant pipe to form a refrigeration cycle. The indoor heat exchanger includes a throttling device on the refrigerant flow path connecting the first indoor heat exchanger and the second indoor heat exchanger, and the outdoor heat exchanger includes a compressor, an indoor heat exchanger, A plurality of refrigerant flow paths are formed between the refrigerant flow paths, and each refrigerant flow path is provided with an expansion device, and each refrigerant flow path from the compressor to the indoor heat exchanger includes at least one outdoor heat exchanger. It is characterized by.

  Moreover, in the air conditioner according to claim 2, the outdoor heat exchanger forms a plurality of refrigerant flow paths between the compressor and the indoor heat exchanger, and the refrigerant flow paths are arranged on the indoor heat exchanger side. Each is provided with an expansion device and includes an outdoor heat exchanger on the compressor side of each refrigerant flow path.

  In the air conditioner according to claim 3, the outdoor heat exchanger is characterized in that the outdoor heat exchanger is disposed between the compressor and the plurality of refrigerant flow paths.

  Moreover, in the air conditioner according to claim 4, the outdoor heat exchanger forms a plurality of refrigerant channels through the heat exchanger between the compressor and the indoor heat exchanger, and each refrigerant channel Each is provided with an expansion device, and is constituted by a refrigerant flow path including an outdoor heat exchanger and a refrigerant flow path not including an outdoor heat exchanger.

  In the air conditioner according to claim 5, when the outdoor heat exchanger provided in each of the plurality of refrigerant flow paths is a first outdoor heat exchanger and a second outdoor heat exchanger, The outdoor heat exchanger and the second outdoor heat exchanger are installed in parallel to the air flow direction.

  The air conditioner according to claim 6 is characterized in that the volumes of the plurality of refrigerant flow paths are substantially equal.

  The air conditioner according to claim 7 has a dehumidifying operation mode in which one of the indoor heat exchangers is an evaporator and the other is a condenser. It is characterized in that a part thereof is fully opened and the throttle amount of the throttle device of another refrigerant flow path is controlled.

  In an air conditioner according to an eighth aspect of the present invention, the opening degree of the expansion device that controls the amount of expansion is controlled in accordance with the refrigerant temperature in the first indoor heat exchanger.

  Further, in the air conditioner according to claim 9, outdoor heat exchange in which the refrigerant temperature on the most downstream side of the outdoor heat exchanger connected to the fully-opened expansion device is connected to the control side of the expansion amount for the plurality of refrigerant flow paths. The temperature is controlled to be lower than the refrigerant temperature on the most downstream side of the vessel.

  The air conditioner according to claim 10 is characterized in that, for the plurality of refrigerant flow paths, a pipe connected to the side farther from the indoor unit of the expansion device has a means for measuring the temperature. .

  In the air conditioner according to claim 11, the throttle device is characterized in that the throttle amount can be continuously changed.

  In an air conditioner according to a twelfth aspect of the present invention, the throttle amount of the throttle device is controlled in accordance with the refrigerant gas temperature discharged from the compressor.

  According to the present invention, the excess refrigerant can be stored in a part of the outdoor heat exchanger during the dehumidifying operation without reducing the efficiency during the cooling operation, and the pressure rise during the dehumidifying operation Therefore, an air conditioner with high energy saving can be provided.

The figure which shows the example of the air conditioner provided with the refrigerating-cycle structure which concerns on Example 1 of this invention. The figure which shows the example of the air conditioner provided with the refrigerating-cycle structure which concerns on Example 2 of this invention. The figure which showed the model which looked at the outdoor heat exchanger 10 of Example 2 from the cross-sectional direction perpendicular | vertical to the axis | shaft of a heat exchanger tube. The figure which shows the structure of the general refrigerating cycle used for an air conditioner provided with the operation mode of air_conditionaing | cooling operation, heating operation, and dehumidification operation. The figure which shows an example of a structure of the heat exchanger used for a refrigerating cycle. The figure which shows the outdoor unit structure which concerns on Example 3 of this invention. The figure which shows the outdoor unit structure which concerns on Example 4 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  A refrigeration cycle configuration according to Embodiment 1 of the present invention will be described with reference to FIG.

  FIG. 1 shows an example of an air conditioner having the refrigeration cycle configuration of the first embodiment. In this configuration, the outdoor heat exchanger 10 in the refrigeration cycle used in the general air conditioner shown in FIG. 4 is divided into a first outdoor heat exchanger 10A and a second outdoor heat exchanger 10B. It is installed so as to be parallel when viewed from the refrigerant flow direction and also parallel to the air flow direction.

  Further, a second expansion device 32A is provided on the far side of the compressor 2 as viewed from the refrigerant flow direction of the outdoor heat exchanger 10A so as to control the flow rate of the refrigerant flowing through the outdoor heat exchanger 10A. A third expansion device 32B is provided on the far side of the compressor 2 as viewed from the refrigerant flow direction of the outdoor heat exchanger 10B so as to control the flow rate of the refrigerant flowing through the outdoor heat exchanger 10B.

  As shown in FIG. 1, the configuration of the first embodiment is different from the conventional configuration of FIG. 4 in the configuration of the outdoor unit 1, and the configuration of the indoor unit 5 is not changed. Further, as the configuration of the outdoor unit 1, it can be said that there are a plurality of refrigerant flow paths P extending from the four-way valve 3 to the connection pipe 8, and each of the refrigerant flow paths P is provided with expansion devices 32A and 32B. In the case of the first embodiment, the first outdoor heat exchanger 10A and the second expansion device 32A are disposed in the first refrigerant flow path P1, and the second outdoor heat is provided in the second refrigerant flow path P2. The exchanger 10B and the third diaphragm device 32B are arranged.

  Next, the operation of each element when the configuration of the refrigeration cycle of Example 1 is used in each operation mode of cooling operation, heating operation, and dehumidification operation will be described with reference to FIG. In the following description of the first embodiment, the operation of each element in the cooling operation and the heating operation is basically the same as that in the conventional example. Is different.

  First, in the cooling operation mode, the high-pressure gaseous refrigerant compressed by the compressor 2 is condensed by dissipating heat to the outside air in the first outdoor heat exchanger 10A and the second outdoor heat exchanger 10B, and the high-pressure liquid refrigerant Becomes a refrigerant. The liquid refrigerant exiting from the first outdoor heat exchanger 10A is decompressed by the action of the second expansion device 32A, and the liquid refrigerant exiting from the second outdoor heat exchanger 10B is decompressed by the action of the third expansion device 32B. Thus, a low-temperature and low-pressure gas-liquid two-phase state is established and flows to the indoor unit 5 through the connection pipe 8.

  The refrigerant that has entered the indoor unit 5 evaporates by absorbing the heat of the indoor air in the first indoor heat exchanger 21 and the second indoor heat exchanger 22. The refrigerant evaporated in the indoor unit 5 returns to the outdoor unit 1 through the connection pipe 7 and is compressed again by the compressor 2 through the four-way valve 3. At this time, the first aperture device 31 is fully open.

  In the heating operation mode, the refrigerant flow path is switched by the four-way valve 3, and the high-pressure gaseous refrigerant compressed by the compressor 2 flows to the indoor unit 5 through the four-way valve 3 and the connection pipe 7. The refrigerant that has entered the indoor unit 5 is condensed by dissipating heat to the indoor air in the second indoor heat exchanger 22 and the first indoor heat exchanger 21, and becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows to the outdoor unit 1 through the connection pipe 8.

  The high-pressure liquid refrigerant that has entered the outdoor unit 1 is decompressed by the action of the second throttling device 32A and the third throttling device 32B, and enters a low-temperature low-pressure gas-liquid two-phase state. The two-phase refrigerant decompressed by the second expansion device 32A flows into the first outdoor heat exchanger 10A, and the two-phase refrigerant decompressed by the third expansion device 32B is the second outdoor heat. It flows into the exchanger 10B, evaporates by absorbing the heat of the outdoor air, and becomes a gaseous refrigerant. In the first outdoor heat exchanger 10 </ b> A and the second outdoor heat exchanger 10 </ b> B, the gaseous refrigerant passes through the four-way valve 3 and is compressed again by the compressor 2. Also in the case of the main heating operation mode, the first expansion device 31 is in a fully opened state as in the cooling operation mode.

  Next, the operation of each element in the dehumidifying operation mode will be described. In this dehumidifying operation mode, the flow direction of the refrigerant is the same as in the cooling operation mode. That is, the high-pressure gaseous refrigerant compressed by the compressor 2 passes through the first outdoor heat exchanger 10A and the second expansion device 32A, or the second outdoor heat exchanger 10B and the third expansion device 32B. After that, it flows to the indoor unit 5 through the connection pipe 8.

  The refrigerant that has entered the indoor unit 5 is condensed by dissipating heat to the indoor air in the first indoor heat exchanger 21, and becomes a high-pressure liquid refrigerant. The liquid refrigerant coming out of the first indoor heat exchanger 21 is reduced in pressure by the action of the first throttling device 31 to become a low-temperature and low-pressure gas-liquid two-phase state, and the second indoor heat exchanger 22 Evaporates by absorbing heat. The refrigerant evaporated in the second indoor heat exchanger 22 returns to the outdoor unit 1 through the connection pipe 7 and flows again to the compressor 2 through the four-way valve 3.

  In the dehumidifying operation mode, when the temperature of the refrigerant in the first indoor heat exchanger 21 is higher than a predetermined temperature calculated from the outside air temperature and the room air temperature, it can be estimated that the refrigerant is excessive. In this case, the opening of one of the second expansion device 32A or the third expansion device 32B is controlled so that the temperature of the first indoor heat exchanger 21 is maintained at a desired temperature, and the other expansion device is controlled. The opening of the device is fully open.

  Here, the case where the opening degree of the second expansion device 32A is controlled and the third expansion device 32B is fully opened will be described as an example. When controlling the opening degree of the second expansion device 32A, in the first outdoor heat exchanger 10A located upstream of the second expansion device 32A in the refrigerant flow direction, the high-temperature and high-pressure gaseous refrigerant flowing from the compressor 2 is Then, it is cooled and liquefied by the outside air. As a result, a part of the excessive refrigerant is held in a liquid state in the first outdoor heat exchanger 10A, and the high-pressure side of the cycle, that is, the compressor discharge pressure is lowered.

  On the other hand, since the third expansion device 32B is fully open, most of the high-temperature and high-pressure gaseous refrigerant that exits the compressor passes through the second outdoor heat exchanger 10B and is cooled by the outside air. The third expansion device 32B is left in the gaseous refrigerant or the two-phase state. At this time, if the second expansion device 32A is not fully closed, it is mixed with the liquid refrigerant liquefied in the first outdoor heat exchanger 10A and then flows to the indoor unit 5.

  Thus, when storing the refrigerant in the first outdoor heat exchanger 10A as a liquid state, the temperature of the refrigerant flowing into the second expansion device 32A from the first outdoor heat exchanger 10A, or the first outdoor Since the refrigerant is liquefied at the outlet portion of the heat exchanger 10A close to the second expansion device 32A, the gaseous or two-phase state flows to the third expansion device 32B via the second outdoor heat exchanger 10B. The temperature is controlled to be lower than the temperature of the refrigerant.

  In the first embodiment, the case where the opening degree of the second expansion device 32A is controlled has been described as an example. However, the same effect can be obtained even when the opening amount of the third expansion device 32B is controlled. Which of the second expansion device 32A and the third expansion device 32B is controlled depends on the first outdoor heat exchanger 10A or the second outdoor heat exchanger 10B in which each expansion device controls the flow of the refrigerant. What is necessary is just to determine according to arrangement | positioning, the volume of a refrigerant flow path, etc.

  For example, when the first outdoor heat exchanger 10A and the second outdoor heat exchanger 10B are installed in the vertical direction, it is better to store the refrigerant liquid in the lower heat exchanger in consideration of the action of gravity. Since the refrigerant liquid can be easily stored, the opening degree of the expansion device that can control the refrigerant flowing through the heat exchanger arranged on the lower side in the vertical direction may be controlled.

  Further, when there is a difference in the volume of the refrigerant flow path P between the first outdoor heat exchanger 10A and the second outdoor heat exchanger 10B, when it is determined that the amount of refrigerant to be stored is large, the refrigerant What is necessary is just to control the opening degree of the expansion | swelling apparatus which can control the refrigerant | coolant which flows through the outdoor heat exchanger by the side with much volume of the flow path P. FIG. At this time, the amount of refrigerant to be stored may be determined based on the temperature difference between the refrigerant temperature in the first indoor heat exchanger 21 described above and a predetermined temperature calculated from the outside air temperature and the room air temperature. .

  The refrigerant that has entered the indoor unit 5 is condensed by dissipating heat to the indoor air in the first indoor heat exchanger 21, and becomes a high-pressure liquid refrigerant. The liquid refrigerant coming out of the first indoor heat exchanger 21 is reduced in pressure by the action of the first throttling device 31 to become a low-temperature and low-pressure gas-liquid two-phase state, and the second indoor heat exchanger 22 Evaporates by absorbing heat. The refrigerant evaporated in the second indoor heat exchanger 22 returns to the outdoor unit 1 through the connection pipe 7 and flows again to the compressor 2 through the four-way valve 3.

  In the configuration of the outdoor unit 1 in FIG. 1, when the first outdoor heat exchanger 10 </ b> A and the second outdoor heat exchanger 10 </ b> B are installed in parallel to the air flow direction, the cooling operation mode and the heating operation are performed. In the mode, the temperature of the air flowing into the first outdoor heat exchanger 10A and the second outdoor heat exchanger 10B can be made equal, and the heat exchanger can be used efficiently. Not only the dehumidifying operation mode but also the cooling operation and the heating operation Efficient operation is possible even in the mode.

  Further, if the flow path lengths of the first outdoor heat exchanger 10A and the second outdoor heat exchanger 10B are substantially equal, the liquid refrigerant flowing from the indoor unit 5 is considered in the refrigerant flow in the heating operation mode. Is distributed in front of the second throttling device 32A and the third throttling device 32B, and it is not necessary to provide resistance on the pipeline in order to adjust the flow rate distribution of the refrigerant. Thus, since it is not necessary to add a resistance for adjusting the flow rate distribution of the refrigerant, it is possible to perform an operation with little loss in each operation mode.

  Further, in the configuration of the indoor unit 5 in FIG. 1, if the first throttle device 31 is configured to be able to continuously change the throttle amount, control suitable for the state of the indoor load is possible, and higher energy saving performance is achieved. can get. Specifically, when the first throttling device 31 is configured to be able to continuously change the throttling amount, when the rotation speed of the compressor is variable according to the state of the indoor load, the second indoor heat exchanger The evaporating pressure of the refrigerant in 22 can be finely controlled, and high energy saving can be realized.

  At this time, the throttle amount of the first throttling device 31 represents the target refrigerant gas temperature discharged from the compressor or the refrigerant gas temperature discharged from the compressor, which is determined from the outside air temperature, the room air temperature, and the rotation speed of the compressor. What is necessary is just to control so that a physical quantity becomes a target value.

  As described above, by using the refrigeration cycle of Example 1, surplus refrigerant can be stored as liquid refrigerant in a part of the outdoor heat exchanger in the dehumidifying operation mode, and further, in the cooling operation mode, In a configuration in which the portion where the high-temperature and high-pressure refrigerant gas discharged from the compressor flows and the portion where the low-temperature and low-pressure two-phase refrigerant flowing out of the second or third expansion device flows are in thermal contact with each other through a pipe or the like Therefore, it is possible to ensure energy saving in the cooling operation mode.

  A second embodiment according to the present invention will be described with reference to FIGS. The basic configuration of the refrigeration cycle in the second embodiment is the same as that in the first embodiment, and only the differences will be described here.

  FIG. 2 shows the configuration of the refrigeration cycle of Example 2. In Example 2, when viewed from the refrigerant flow direction in the cooling operation or the dehumidifying operation mode, the pipe connecting the four-way valve 3 and the outdoor heat exchanger 10 branches into two pipes at the branch point 201 and is branched Then, after passing through the outdoor heat exchanger 10 and passing through the second expansion device 32A and the third expansion device 32B provided on the respective pipelines, the flow is merged at the merge point 202.

  FIG. 3 is a schematic view of the outdoor heat exchanger 10 according to the second embodiment as viewed from the cross-sectional direction perpendicular to the axis of the heat transfer tube. The broken line in the figure indicates the refrigerant flow path in the outdoor heat exchanger 10.

  In Example 2, the outdoor heat exchanger 10 is configured in two rows with respect to the air flow direction, and the configuration of the refrigerant flow path P is a branch point when viewed from the refrigerant flow direction in the cooling operation and the dehumidifying operation mode. After branching at 201, each of the flow paths P1 and P2 is further split into two and merges after passing through the heat transfer pipe on the downstream side in the air flow direction, and flows in the two flow paths on the upstream side in the air flow direction. It has a configuration.

  The two refrigerant flow paths P1 and P2 exiting the outdoor heat exchanger 10 are respectively provided with a second expansion device 32A and a third expansion device 32B, and then merge at the junction 202. It has become.

  As described above, a plurality of refrigerant flow paths P flowing through the heat exchanger 10 are configured, and a plurality of expansion devices 32 are provided on the outlet side in the cooling operation and the dehumidification operation mode, and the opening degree of each expansion device 32 is appropriately controlled. By doing so, it becomes possible to store excess refrigerant in the partial flow path of the outdoor heat exchanger in the dehumidifying operation mode without dividing the heat exchanger.

  Further, if the flow path lengths constituting the refrigerant flow paths P1 and P2 are made equal, the entire heat exchanger can be used efficiently in the cooling operation or heating operation mode.

  Also in the second embodiment, as the configuration in the outdoor unit 1, there are a plurality of refrigerant flow paths P extending from the four-way valve 3 to the connection pipe 8, and each refrigerant flow path P is provided with expansion devices 32A and 32B, respectively. it can. Also in the case of the second embodiment, the first outdoor heat exchanger 10A and the second expansion device 32A are disposed in the first refrigerant flow path P1, and the second outdoor heat is provided in the second refrigerant flow path P2. The exchanger 10B and the third diaphragm device 32B are arranged.

  The configuration of the refrigerant flow path in FIG. 3 is merely an example, and the number of refrigerant flow paths may be appropriately designed according to the capacity and the amount of refrigerant circulation, and the same effect is obtained regardless of the number of refrigerant flow paths. However, since increasing the number of aperture devices leads to an increase in cost, considering the suppression of the increase in cost, it is desirable that the number of aperture devices be about two.

  In Example 3, an example of forming a plurality of refrigerant flow paths capable of realizing the above concept of the present invention will be described with reference to FIG.

  FIG. 6 shows a configuration in which a bypass pipe is provided between the middle and the other end of the two heat exchangers 10C and 10D connected in series. The third expansion device 32B is arranged in series with the heat exchanger 10D to form the second refrigerant flow path P2, and the second expansion device 32A is arranged in the bypass pipe to form the first refrigerant flow path P1. doing. The arrangement positions of the second and third expansion devices 32A and 32B are on the downstream side when viewed from the refrigerant flow direction in the cooling operation or the dehumidifying operation mode.

  In the arrangement of the third embodiment, the second expansion device 32A on the bypass piping side is fully opened, and the third expansion device 32B disposed in series with the heat exchanger 10D is on the control side. Is good.

  Also in the third embodiment, as a configuration in the outdoor unit 1, there are a plurality of refrigerant flow paths P extending from the four-way valve 3 to the connection pipe 8, and each refrigerant flow path P is provided with expansion devices 32A and 32B, respectively. it can. However, in the case of Example 3, only the second expansion device 32A is disposed in the first refrigerant flow path P1, and the outdoor heat exchanger 10D and the third expansion device 32B are disposed in the second refrigerant flow path P2. Are arranged.

  In Example 4, an example of forming a plurality of refrigerant flow paths capable of realizing the above concept of the present invention will be described with reference to FIG.

  FIG. 7 shows a configuration in which a bypass pipe is provided between the middle and the other end of the two heat exchangers 10C and 10D connected in series. The third expansion device 32B is arranged in series with the heat exchanger 10D to form the second refrigerant flow path P2, and the heat exchanger 10E and the second expansion device 32A are arranged in the bypass pipe to form the first refrigerant. A flow path is formed. The arrangement positions of the second and third expansion devices 32A and 32B are on the downstream side when viewed from the refrigerant flow direction in the cooling operation or the dehumidifying operation mode.

  In the arrangement of the fourth embodiment, either the second diaphragm device 32A or the third diaphragm device 32B may be the control side.

  Also in the fourth embodiment, as the configuration in the outdoor unit 1, there are a plurality of refrigerant flow paths P extending from the four-way valve 3 to the connection pipe 8, and each refrigerant flow path P is provided with expansion devices 32A and 32B, respectively. it can. However, in the case of Example 4, the outdoor heat exchanger 10E and the second expansion device 32A are arranged in the first refrigerant flow path P1, and the outdoor heat exchanger 10D and the second heat expansion apparatus 32A are arranged in the second refrigerant flow path P2. 3 throttling devices 32B are arranged.

1: Outdoor unit 2: Compressor 3: Four-way valve 4: Propeller fan 5: Indoor unit 6: Cross-flow fan 10A: First outdoor heat exchanger 10B: Second outdoor heat exchanger 21: First indoor heat exchange Unit 22: Second indoor heat exchanger 31: First expansion device 32A: Second expansion device 32B: Third expansion device

Claims (9)

An air conditioner in which at least a compressor, an outdoor heat exchanger, and an indoor heat exchanger are connected by a refrigerant pipe to form a refrigeration cycle,
The indoor heat exchanger includes a throttle device on a refrigerant flow path connecting the first indoor heat exchanger and the second indoor heat exchanger,
The refrigerant flow path between the compressor and the indoor heat exchanger is provided on the indoor heat exchanger side of the outdoor heat exchanger and the outdoor heat exchanger, and the refrigerant flow rate that flows to the outdoor heat exchanger An air conditioner characterized in that at least two sets of the throttle devices arranged in series are arranged in parallel. The air conditioner according to claim 1,
In the refrigerant flow path between the compressor and the indoor heat exchanger, a first outdoor heat exchanger, a second outdoor heat exchanger, and a throttle device are arranged in series in this order, and the first An air conditioner characterized in that the third outdoor heat exchanger and the expansion device are arranged in series in this order by branching from a connection portion between the outdoor heat exchanger and the second outdoor heat exchanger. The air conditioner according to claim 1,
For a set in which the outdoor heat exchanger and the expansion device are arranged in series, when each of the outdoor heat exchangers is a first outdoor heat exchanger and a second outdoor heat exchanger, the first heat exchanger The outdoor heat exchanger and the second outdoor heat exchanger are installed in parallel to the air flow direction. An air conditioner according to any one of claims 1 to 3 ,
The air conditioner characterized in that the volume of the refrigerant flow path of each set is substantially equal for the set in which the outdoor heat exchanger and the expansion device are arranged in series. An air conditioner according to any one of claims 1 to 4 ,
A dehumidifying operation mode in which one of the indoor heat exchangers is an evaporator and the other is a condenser;
In the dehumidifying operation mode, an air conditioner characterized in that a part of the expansion device on the outdoor heat exchanger side is fully opened and the amount of expansion of another expansion device on the outdoor heat exchanger side is controlled. The air conditioner according to claim 5 ,
An air conditioner that controls an opening degree of a throttle device on a side that controls the throttle amount in accordance with a refrigerant temperature in the first indoor heat exchanger. The air conditioner according to claim 5 or 6 ,
On the outdoor heat exchanger side, the refrigerant temperature on the most downstream side of the outdoor heat exchanger connected to the expansion device that is fully opened leads to the refrigerant on the most downstream side of the outdoor heat exchanger connected to the side that controls the amount of expansion. An air conditioner that is controlled to be lower than the temperature. An air conditioner according to any one of claims 1 to 7 ,
The air conditioner characterized in that the aperture device can continuously change the aperture amount. The air conditioner according to claim 8 ,
An air conditioner characterized in that the throttle amount of the throttle device is controlled according to the refrigerant gas temperature discharged from the compressor.

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